I have a problem with anchoring a Fixedpoint2D on a 2D object. The fixed point is used to make a circle "sticky" and I have no problem doing so IF the object that will stick to it is at a rotation of (0,0,0)
HOWEVER, if I rotate the object that will stick to it on the z axis, the anchoring point changes to a rotated point on the edge of the circle at the moment of contact. I want to find out what is causing this since I do not use the objects rotation in any of my calculations for the anchoring point.
Can anybody help me? I am relatively new to unity.
void OnCollisionEnter2D(Collision2D c)
{
if (hit != true)
{
Debug.Log("STICK");
FixedJoint2D joint = gameObject.AddComponent<FixedJoint2D>();
joint.connectedBody = c.rigidbody;
//calculate new anchor point
float newX = gameObject.transform.position.x - c.gameObject.transform.position.x;
float newY = gameObject.transform.position.y - c.gameObject.transform.position.y;
Vector3 v = new Vector3();
v.x = newX;
v.y = newY;
v.z = 0;
joint.connectedAnchor = v;
}
}
FixedJoint2D component is on the Large circle,
Transform rotation of the small object LEFT = (0,0,0), RIGHT = (0,0,90)
Related
How do I calculate the distance of a game object (inside a cube collider) from the cube collider surface? The existing calculations were made from the cube surface outwards so I got 0 when I used the collider.closestpoint or collider.closestpointonbounds.
The simplest (but computationally not the cheapest) would be to not rely on your current collider for the distance, but to add a set of small colliders around the edge of the object (so 6 colliders, one per face of the cube). Using Collider.ClosestPoint() on all 6 faces and calculating the distance like that would give you the results you need.
First convert a point to local space.
var localPoint = transform.InverseTransformPoint(worldPoint);
var extents = collider.size * 0.5f;
var closestPoint = localPoint;
Compute the distance to each face.
var disx = extents.x - Mathf.Abs(localPoint.x);
var disy = extents.y - Mathf.Abs(localPoint.y);
var disz = extents.z - Mathf.Abs(localPoint.z);
Find the closest face (smallest distance) and move the closest point along this axis.
if(disx < disy)
{
if (disx < disz)
closestPoint.x = extents.x * Mathf.Sign(localPoint.x); //disx
else
closestPoint.z = extents.z * Mathf.Sign(localPoint.z); //disz
}
else
{
//......
}
Plus the offset of the collider, convert to world space.
closestPoint += collider.center;
transform.TransformPoint(closestPoint);
I don't know how efficient this is, but here is how I solved it:
public static Vector3 ClosetPointOnBounds(Vector3 point, Bounds bounds)
{
Plane top = new Plane(Vector3.up, bounds.max);
Plane bottom = new Plane(Vector3.down, bounds.min);
Plane front = new Plane(Vector3.forward, bounds.max);
Plane back = new Plane(Vector3.back, bounds.min);
Plane right = new Plane(Vector3.right, bounds.max);
Plane left = new Plane(Vector3.left, bounds.min);
Vector3 topclose = top.ClosestPointOnPlane(point);
Vector3 botclose = bottom.ClosestPointOnPlane(point);
Vector3 frontclose = front.ClosestPointOnPlane(point);
Vector3 backclose = back.ClosestPointOnPlane(point);
Vector3 rightclose = right.ClosestPointOnPlane(point);
Vector3 leftclose = left.ClosestPointOnPlane(point);
Vector3 closest = point;
float bestdist = float.MaxValue;
foreach (Vector3 p in new Vector3[] {
topclose, botclose, frontclose, backclose, leftclose, rightclose
})
{
float dist = Vector3.Distance(p, point);
if (dist < bestdist)
{
bestdist = dist;
closest = p;
}
}
return closest;
}
(note: this assumes and axis-aligned box, which is all I needed at the time. If you want to rotate it you will have to do more work to transform the point.)
You can Calculate by Vector3.Distance
some example
float minDistance =2;
float Distance = Vector3.Distance(other.position, transform.position);
if(Distance < minDistance)
{
//some code stuffs
}
else if(Distance > minDistance){
//some code stuffs
}
Useful information about Vector3.Distance and getting Distance from object
source: https://docs.unity3d.com/ScriptReference/30_search.html?q=Distance
I'm trying to write a function so when I hold the mouse down I can drag the game object and then I latch it into target.
I'm using a perspective,vertical camera with physical Camera checked and with focal length 35. Also I don't know if this is important but I am dragging the object in the Y and Z axis.
The code I'm using drags the objects too close to the camera. How can I fix this?
private void OnMouseDrag()
{
if (IsLatched)
{
print($"is latched:{IsLatched}");
return;
}
float distance = -Camera.main.transform.position.z + this.transform.position.z;
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
Vector3 rayPoint = ray.GetPoint(distance);
this.transform.position = rayPoint;
print($"{name} transform.position:{transform.position}");
this.gameObject.GetComponent<Rigidbody>().isKinematic = true;
isHeld = true;
}
You are calculating the distance by subtracting the z coordinates, then taking a point along the click-ray with that distance. That will not be a point on the same z coordinate. If you want to keep one component constant, I would rather intersect the ray with an XY plane.
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
float Zplane = this.transform.position.z; // example. use any Z from anywhere here.
// find distance along ray.
float distance = (Zplane-ray.origin.z)/ray.direction.z ;
// that is our point
Vector3 point = ray.origin + ray.direction*distance;
// Z will be equal to Zplane, unless considering rounding errors.
// but can remove that error anyway.
point.z = Zplane;
this.transform.position = point;
Could this help? Would work similar with any other plane.
Ok, so, i've been stuck on this for ages. Im working on an AI that will navigate a tank to a waypoint, defined as a Vector3. the position of the tank is also defines as a Vector3, both these have their Y position set to 0, as to ignore terrain elevation, the current rotation of the tank is also a Vector3, though only the Y rotation is needed, as i'm effectively projecting the 3d position onto a 2d navigational grid.
The AI passes anywhere between -1 and 1 into the control for the tank, which then handles the physics operations. so, i need to somehow calculate the angle, positive or negative in relation to the current heading angle of the tank to the position of the waypoint, then send the rotation value to the controls. At the moment I simply cant get it working, I feel like iv'e pretty much tried everything.
This is my code currently, it doesn't work, at all, and is about the 20th revision:
void driveToTarget()
{
Vector3 target0 = driveTarget;
target0.y = 0;
GameObject current0Obj = new GameObject();
Vector3 current0 = this.transform.position;
current0.y = 0;
print(current0);
print(target0);
Vector3 current0Angle = this.transform.eulerAngles;
print(current0Angle.y);
current0Angle.x = 0;
current0Angle.z = 0;
Vector3 heading = target0 - current0;
Quaternion headingAngle = Quaternion.LookRotation(heading);
print("headingAngle" + headingAngle);
print("heading direction, allegidly: " + Quaternion.Euler(heading).ToEulerAngles());
Quaternion distanceToGo = Quaternion.Lerp(Quaternion.Euler(current0Angle), headingAngle, 0.01f);
float angle = Vector3.SignedAngle(current0, target0, Vector3.up);
float difference = Mathf.Abs(angle - current0Angle.y);
print("heading angle " + angle);
if (current0 != driveTarget)
{
steeringVal = Mathf.Abs(1.5f-(1f/Mathf.Abs(distanceToGo.y))) * -Mathf.Sign(distanceToGo.y); ;
throttleVal = 0f;
} else
{
throttleVal = 0;
}
}
--EDIT--
So, I've partially solved it, and now encountered another problem, I've managded to get the tank to detect the angle between itself and the waypoint, BUT, rather than orienting forward towards the waypoint, the right side of the tank orients towards it, so it orbits the waypoint. I actually know why this is, becasue the forward vector of the tank is technically the right vector because of unity's stupid axis ruining my blender import, anyway, heres the updated code:
void driveToTarget()
{
Vector3 target0 = driveTarget;
target0.y = 0;
Vector3 current0 = this.transform.position;
current0.y = 0;
print("Current: " + current0);
print("Target: " + target0);
Vector3 current0Angle = this.transform.rotation.eulerAngles;
print("Curret rotation:" + current0Angle.y);
current0Angle.x = 0;
current0Angle.z = 0;
Vector3 heading = target0 - current0;
Quaternion headingAngle = Quaternion.LookRotation(heading);
print("heading angle: " + headingAngle.ToEuler());
float distanceToGo = (current0Angle.y) - headingAngle.eulerAngles.y;
print("DistanceToGo: " + distanceToGo);
if (current0 != driveTarget)
{
steeringVal = 1 * -Mathf.Sign(distanceToGo);
throttleVal = 0f;
} else
{
throttleVal = 0;
}
Debug.DrawRay(current0, heading, Color.red, 1);
Debug.DrawRay(current0, this.transform.up, Color.red, 1);
}
I'm not sure exactly how your code is setup or how the steering works. You may want to look into using the Unity NavMeshAgent to simplify this.
Regardless here is some code I wrote up that takes a destination and rotates an object towards it. All you'd have to do from there is move the object forwards.
Vector3 nextDestination = //destination;
Vector3 direction = nextDestination - transform.position;
direction = new Vector3(direction.x, 0, direction.z);
var newRotation = Quaternion.LookRotation(direction);
var finalRotation = Quaternion.Slerp(transform.rotation, newRotation, Time.deltaTime); //smoothes out rotation
transform.rotation = finalRotation;
Sorry if this isn't what you needed. Have you been able to figure out which part of the code is behaving unexpectedly from your print statements?
tl;dr Moving my game from Processing to Unity. Code responsible for grappling by manually changing the player's velocity doesn't work even though it's basically copy/pasted.
Hi, I've been working on a project of mine over the summer on Processing, and last week I decided to translate it over to Unity.
What I'm having a problem with is the grapple/rope physics. It's supposed to essentially keep the player inside a circle (made by the endpoint of the rope and the length of the rope). When the player falls outside of this circle, the player's position is moved back to the edge of the circle and the player's velocity is set to tangent of the circle.
Decreasing the length of the rope while swinging is supposed to speed you up. (See Floating Point)
On Processing, it works perfectly just as described above, but when I basically copy/pasted the code into unity it loses momentum too quickly (always ends up stopping at the same angle on the other side the player started on). Here is the code for both (run on each physics frame):
(I've also made some images to describe the motion that both versions produce)
Processing
Code
(warning: bad and redundant)
physics update:
exists = (endPoint != null);
if(lgth<=0) lgth = 1;
if(exists) {
currentLength = phs.position.dist(endPoint);
if(currentLength > lgth) {
float angle = getAngle(endPoint, phs.position);
phs.addPosition(abs(currentLength - lgth), angle);
float angleBetween = getAngle(phs.position, endPoint);
PVector relativeVelocity = new PVector(phs.velocity.x + phs.position.x, phs.velocity.y + phs.position.y);
float displacement = angleBetween - 90;
Line l1 = lineFromTwoPoints(relativeVelocity, endPoint);
Line l2 = lineFromAngle(phs.position, displacement);
PVector pointToLerpTo = intersection(l1, l2);
if(pointToLerpTo!=null) {
phs.velocity.x = pointToLerpTo.x-phs.position.x;
phs.velocity.y = pointToLerpTo.y-phs.position.y;
}
else phs.velocity.mult(0);
}
}
when the player shortens the rope, speed increases:
if(exists) {
float newLgth = lgth-d;
float distance = getDistance(phs.position, endPoint);
if(distance > newLgth) {
float ratio = (distance-newLgth)/lgth;
phs.velocity.setMag(phs.velocity.mag()*(1+ratio));
}
lgth = newLgth;
}
Motion from Processing (good)
Player starts by moving downwards at left edge of rope circle. Doesn't lose speed and continues going around multiple times until gravity slows it down.
Unity
Code
both code blocks from above are handled in the same place here, under FixedUpdate() (problematic part seems to be the velocity section)
distance = Vector2.Distance(transform.position, endpoint);
if(connected && distance > length) {
//lerp position -> endpoint// keep gameObject within length of the rope
float posLerpAmount = (distance - length) / distance;
transform.position = Vector2.Lerp(transform.position, endpoint, posLerpAmount);
//'lerp' velocity -> endpoint// keep the velocity locked to the tangent of the circle around the endpoint
Vector2 relativeVelocity = GetComponent<Rigidbody2D>().velocity + (Vector2)transform.position;
Line l1 = Geometry.LineFromTwoPoints(relativeVelocity, endpoint);
Line l2 = Geometry.LineFromAngle(transform.position, Geometry.GetAngle(endpoint, transform.position) - 90);
if(!Geometry.AreParallel(l1, l2)) {
Vector2 pointToLerpTo = Geometry.Intersection(l1, l2) - (Vector2)transform.position;
GetComponent<Rigidbody2D>().velocity = pointToLerpTo;
}
else GetComponent<Rigidbody2D>().velocity = new Vector2(0, 0);
//increases the magnitude of the velocity based on how far the rope moved the object's position
float ratio = (distance - length) / length;
GetComponent<Rigidbody2D>().velocity *= 1 + ratio;
distance = length;
}
Motion from Unity (bad)
Player starts by moving downward at left edge of rope circle. Gains a little bit of speed from gravity, then will always stop 45 degrees on the other side where it started (regardless of starting speed), then slowly fall back down to the bottom of the circle.
If anyone needs me to explain the Geometry class (lines, intersections) then I can, but I think it's mostly self-explanatory. Otherwise, I think I explained this the best I could. Thanks in advance for any help.
(also, StackOverflow isn't letting me add the Unity2d tag so I guess I gotta settle for Unity3d)
I found out that Rigidbody2D.velocity.magnitude is not how far the object moves every physics update. This is what was causing the issue, because the Processing code was based off the velocity being added directly to the position every update.
To fix this, what I did was do the same geometry, but scale the velocity to the % of how much of the velocity was actually 'used' (it usually travels 2% of the actual velocity vector).
Here is the final code in Unity: (this time I'm showing the fill FixedUpdate(), with the irrelevant parts removed)
float lastMagnitude;
Vector2 lastPosition;
void FixedUpdate() {
float velocityMoved = Vector2.Distance(lastPosition, transform.position) / lastMagnitude;
Debug.Log(velocityMoved * 100 + "%"); //this is usually 2%
bool shortenedRope = false;
if(Input.GetButton("Shorten Rope")) {
shortenedRope = true;
length -= ropeShortenLength;
}
distance = Vector2.Distance(transform.position, endpoint);
if(connected && distance > length) {
//lerp position -> endpoint// keep gameObject within length of the rope
float posLerpAmount = (distance - length) / distance;
transform.position = Vector2.Lerp(transform.position, endpoint, posLerpAmount);
//'lerp' velocity -> endpoint// keep the velocity locked to the tangent of the circle around the endpoint
Vector2 adjustedVelocity = rigidbody.velocity * velocityMoved;
Vector2 relativeVelocity = adjustedVelocity + (Vector2)transform.position;
Line l1 = Geometry.LineFromTwoPoints(relativeVelocity, endpoint);
Line l2 = Geometry.LineFromAngle(transform.position, Geometry.GetAngle(endpoint, transform.position) - 90);
if(!Geometry.AreParallel(l1, l2)) {
Vector2 pointToLerpTo = Geometry.Intersection(l1, l2) - (Vector2)transform.position;
rigidbody.velocity = pointToLerpTo;
rigidbody.velocity /= velocityMoved;
}
else rigidbody.velocity = new Vector2(0, 0);
//'give back' the energy it lost from moving it's position
if(shortenedRope) {
float ratio = (distance - length) / length;
rigidbody.velocity *= 1 + ratio;
}
distance = length;
}
lastPosition = transform.position;
lastMagnitude = rigidbody.velocity.magnitude;
}
EDIT: Recently learned that it is better to use Time.deltaFixedTime instead of the variable I made velocityMoved, since Time.deltaFixedTime is already calculated.
Suppose you have a camera projection matrix, i.e. camera translation vector + rotation quaternion, like every typical camera, it is able to move and rotate in any direction. And independent of it's rotation whether it is looking forward, upward or downward I need to show a compass-like gauge pointing where the camera is targeted at.
The problem is that when the camera is pointed downwards the rotation of camera around it's optical center defines the value of the compass, but when the camera points forward, the rotation of camera around it's center no longer affects the value of compass, in this case the direction of camera defines the value of compass.
It get's more ugly when the camera is tilted downwards only 45 degrees, in this case it is not even clear whether the rotation around camera center affects rotation of compass.
So is there an elegant way of getting the compass value based on arbitrary camera projection matrix / quaternion?
Thank you in advance!
If you want just an arrow pointing at the target its:
Transform camera = Camera.main.transform;
Transform target = Target.transform;
Vector3 relativePosition = target.position - camera.position;
Vector3 targetRelative = Vector3.ProjectOnPlane(relativePosition, camera.forward);
float angle = Angle360(camera.up, targetRelative, camera.forward);
Compass.transform.rotation = Quaternion.Euler(0, 0, angle);
The angle function is:
float Angle360(Vector3 from, Vector3 to, Vector3 normal)
{
float dot = Vector3.Dot(from, to);
float det = Vector3.Dot(normal, Vector3.Cross(from, to));
return Mathf.Atan2(det, dot)*Mathf.Rad2Deg;
}
Here is how you can get the direction of the compass in worldspace:
Project the camera direction and target position on the XZ plane
Transform camera = Camera.main.transform;
Transform target = Target.transform;
Vector3 cameraWorldDirXZ = Vector3.ProjectOnPlane(camera.forward, Vector3.up).normalized;
Vector3 targetWorldDirXZ = Vector3.ProjectOnPlane(target.position, Vector3.up).normalized;
The angle between the cameraWorldDirXZ and targetWorldDirXZ is the angle of your compass needle.
But i don't think this will behave like you think it will. This gives you the angle that you need to rotate the camera.forward vector around the y axis to face the target. If you rotate around camera.forward you don't change either the camera.forward vector or the y axis so the compass wont change.
You might want to try a compass in local space. For that you project onto the camera XZ plane:
Vector3 cameraLocalDirXZ = camera.forward;
Vector3 targetLocalDirXZ = Vector3.ProjectOnPlane(target.position, camera.up).normalized;
Again the angle between the cameraLocalDirXZ and targetLocalDirXZ is the angle of your compass needle. This gives you the angle you need to rotate camera.forward around camera.up to face the target. Note that when you rotate around camera.forward it will change camera.up so it will change the compass direction.
If anyone stumbles upon this problem, the solution (thanks to #Pluto) is very simple, multiply your camera quaternion over three axis vectors (0,0,1), (0,1,0), (1,0,0), you will get three vectors defining coordinate system of your camera, project those three vectors onto your plane, find centroid of your three projected points and voila you have compass direction.
Here's the piece of code for that:
var rotation = /* Your quaternion */;
var cameraOrtX = rotation * new Vector3 (1, 0, 0);
var cameraOrtY = rotation * new Vector3 (0, 1, 0);
var cameraOrtZ = rotation * new Vector3 (0, 0, 1);
var cameraOrtPX = Vector3.ProjectOnPlane(cameraOrtX, new Vector3(0, 1, 0));
var cameraOrtPY = Vector3.ProjectOnPlane(cameraOrtY, new Vector3(0, 1, 0));
var cameraOrtPZ = Vector3.ProjectOnPlane(cameraOrtZ, new Vector3(0, 1, 0));
var centroid = (cameraOrtPX + cameraOrtPY + cameraOrtPZ) / 3.0f;